Disazo dyes and process of making same



Penman". 14, 1939 PATENT OFFICE 2,150,191 DISAZO DYES AND PROCESS OF MAKING SAME Swanie Siguard Rossander, Wilmington, Del., as-

signor to E. 1. du Pont de Nemours & Company, Wilmington, Del., a corporation of Delaware No Drawing. Application June 29, 1937, Serial No. 1 50.!)60

8 Claims.

This invention relates to new disazo dyes, characterized by desirable shades of red or scarlet in direct dyeing, and by their substantivity to cotton and regenerated cellulose.

It is an object of this invention to provide azo dyes of red shades and being substantive to cotton and regenerated cellulose. It is a further object of this invention to provide azo dyes having HI? 5 03M MOIS NH wherein the position of the am bridge in the benthe qualities aforementioned, and possessing further the adaptability of. being developed on the fiber to produce orange to red to reddish brown colors of good washing fastness. Other objects of this invention will appear as the description proceeds.

The objects of my invention are attained by tetrazotizing aminobenzoyl-p-tolylene-diamine, and coupling it to two molecules of amino-benzoyl-J-acid.

I have found that the dyestufls thus produced possess commercially desirable shades of red or scarlet; are substantive to cellulose, whether natural or regenerated; are further capable of development on the fiber, for instance with betanaphthol or phenyl-methyl-pyrazolone; and

when so developed produce very bright shades within the range of orange to red to reddish brown, of good fastness to washing. Further- 4 more, the dyeings thus prdduced have excellent discharge qualities.

I am aware of German Patent No. 221,433 which discloses various dyes related in structure to the aforementioned compound forming "the subject matter of this invention. The nearest compounds of the German patent related to my invention are the one prepared from m-aminobenzoyl-mphenylene-diamine and the one from m'-aminobenzoyl-m-tolylene-diamine. However, the dyeings produced by these compounds are of difler- (Cl. H6)

ent shades than those produced by the novel compounds of my invention. My novel dyestuffs, on the other hand, combine the properties of brightness with desirable shade, good washing fastness, good dischargeability and other valuable charac- 5 teristics demanded in the textile dyeing art.

The novel dyestuifs of my invention correspond to the general formula zene ring marked A may be either meta or para, and the positions of the NH: groups in the benzene rings marked B, B may likewise be meta or para. The letter M in the above formula may represent hydrogen or an alkali-metal. As already stated, they may all be developed on the fiber by diazotizing and coupling to various developing components which have the property of rendering an azo dye water-insoluble. 30

The following table gives some of the dyes of this series actually prepared by me, together with their shades upon cotton both by direct dyeing and after development.

Rinse with cold water.

In the above table, MABPTD stands for metaaminobenzoyl para-tolylene-diamine,

0 o NRC-NH:

PABBTD stands for para-aminobenzoyl-paratolylene-diamine, I

. CH1 HzN-O-CONHO-NH:

*mentioned are by weight.

Ewample I .Preparation of M ABJ -acid -M ABPTD M ABJ -acz'd Slurry 48.2 parts of meta'-aminobenzoyl-paratolylene-diamine with 2000 parts of water. Add 36.5 parts of hydrochloric acid. Ice to 5 C. Add 27.6 parts of sodium nitrite as a 30% solution, as rapidly as absorbed. Maintain a distinct excess of nitrite and Congo acidity for 25 minutes.

Charge 161 parts of m'-aminobenzoyl-J-acid in a tub with 1500 parts of water. Add approximately 8.5 parts of ammonia, leaving the solution clear and slightly alkaline to Brilliant Yellow paper. Add 8.4 parts of sodium bicarbonate and 117 parts of sodium carbonate. Ice to 5 0.

Slowly add the tetrazo compound above produced to the alkaline solution of m'-aminobenzoyl-J-acid. Continue stirring for 2 hours. Slowly warm to C. Slowly add 5% salt by weight of the aqueous mass, and filter. Dry the press-cake in an oven at 80-90 C. The dry powder thus obtained is reddish in appearance, and has most probably the constitution represented by the following formula:

COHN B 011% The above dye may be applied to cotton or regenerated cellulose by the direct method, and may be developed into a washing-resistant color on the fiber by tetrazotizing on the fiber and coupling to one of the customary developing components. The following additional example illustrates this procedure. I

Example HP-Dyeing of cellulosic fiber One part of cotton piece goods is dyed. in the usual manner for colors of this series (see for instance the German patent above cited) with four-hundredths parts of the color prepared in ExampleI. The dyed fabric is rinsed in cold water and put in 400 parts of water at 20 C. Add six-tenths parts of sodium nitrite and eighttenths parts of sulfuric acid. Stir 15 minutes. Dissolve two-tenths of beta-naphthol in 400 parts of water and onegoods. Stir 15 minutes.

tenth part of caustic soda. Stir the solution rapidly while adding the above rinsed piece Rinse in cold water and dry. The dyeing is a bright scarlet shade. The probable formula of the dye on the fiber is Example III .Preparation of The procedure is the same as in Example I, except that in lieu of 48.2 parts of meta-aminobenzoyl-para-tolylene-diamine an equal weight of para-aminobenzoyl-para-tolylene-diamine is employed. The dyestufi has similar properties to that of Example I, and when developed upon cotton fiber according to the procedure indicated in Example II, it gives a bright red shade.

It will be understood that my procedure is not limited to the details set forth in the above examples, but may be varied widely within the skill of those familiar with this art. For instance, instead of isolating the color of Example I in the form of Na-salt, it may be isolated in the form of any other alkali-metal salt, or in the form of free acid. In the last mentioned case, the salting-out step is omitted, and in lieu thereof the aqueous alkaline mass, after the coupling step, is acidified by the aid of hydrochloric acid or any other suitable acid, until acid to Congo red, and the precipitated dye is filtered oif, washed and dried.

- N H: mols NHCO-C Likewise, instead of synthesizing the dyestuft by coupling tetrazotized m'- or p'-amino-benzoyl-p-tolylene-diamine to two mols of m'- or p'-aminobenzoyl-J-acid, the tetrazo compound may be coupled first to two mols of J-acid, and

(The details of such alternative procedure If a water-insoluble pigment in substance is desired, the second tetrazotization and development may be done on the product of Example I in substance, and the resulting color recovered in substance, in the usual manner.

Many other variations and modifications will be readily apparent to those skilled in the art.

The dyes of this invention are characterized by bright shades and good substantivity to cotton; and after development on the fiber, for instance with beta-naphthol, they give dyeings which are very fast to washing and possess very vgood discharge qualities.

I claim: I

1. A disazo dyestuil having a structure corresponding, when in the form of alkali-metal salt, to the formula elm.

wherein M is an alkali metal.

2. The process of producing a disazo dye which comprises tetrazotizing an aminobenzoy'l-ptoiylene-diamine and coupling it to two mols of an aminobenzoyl-J-acid. v

3. A tetrakisazo dye having a structure corresponding, when in the form of an alkali-metal salt,to the general formula wherein R is a water-insolubilizing azo dye dettrazotizing the dyestuflsponding, when m the form the Iormula comer 5. A tetrakisazo dye having a structure sponding, when in the form of its the formula on gMUOONH oNn fined in claim 1.-

7. The processor dyeing celluloslc material,

I which comprises applying thereto an aqueous solution of a dyestui! as defined in claim 1, then on the fiber and coupling it with a water-insolubilillng veloping component.

8. The process of dyeing eeilulosic material, which comprises applying thereto an aqueous solution of a dyestui! as defined in claim 1, then tetrasotizing the dyestufl on the fiber and coupling it to beta-naphthol.

BWANIE SIGUARD ROSBANDER.

of its Na-salt. to

Na-salt, to 

